1. Field of the Invention
The present invention relates to a light source support apparatus directed to measurement of the radiation characteristic of light emitted from a light source, and to an optical radiation characteristic measurement apparatus using the light source support apparatus.
2. Description of the Background Art
As an indicator for evaluating the performance of a light source, a measurement of the optical radiation characteristic is known. The luminous intensity distribution characteristic is a typical example of such a measurement of the optical radiation characteristic. The luminous intensity distribution characteristic means a spatial distribution of the luminous intensity of a light source. As such a luminous intensity distribution characteristic, both the absolute-value-based luminous intensity distribution and the relative-value-based luminous intensity distribution are used. The absolute-value-based luminous intensity distribution is a measurement of the spatial distribution of the absolute value of the luminous intensity and is used in such a case where the total luminous flux generated by a light source is to be determined. In contrast, the relative-value-based luminous intensity distribution is a measurement of the spatial distribution of the relative value of the luminous intensity, and is used in such a case where the luminous intensity distribution pattern is to be determined. Generally, it is not easy to measure the luminous intensity distribution characteristic of light sources such as a light source having a complicated luminous intensity distribution pattern and a light source whose optical characteristics and the like are not known.
Regarding such a measurement of the luminous intensity distribution, Japanese Patent Laying-Open Nos. 05-281023, 2005-172665, and 2009-150791, for example, each disclose a configuration for simultaneously measuring respective luminous intensities of a light source at a plurality of different positions in a predetermined irradiation space. The configurations disclosed in these prior art documents cannot be used to measure the luminous intensity distribution characteristic of the light source with respect to all directions.
Japanese Patent Laying-Open No. 2000-258246 discloses a configuration for measuring the total luminous flux, rather than measuring the luminous intensity distribution characteristic itself. In this configuration, it is assumed that a sphere with a radius R has its center at which a light source is located, the spherical surface of this sphere is divided along a plurality of longitudes, a resultant divisional surface defined by one of the longitudes and its adjacent longitude is further divided by a plurality of latitudes to thereby define divisional surface spaces. Photodetectors are arranged in these divisional surface spaces, respectively. Then, the light source is rotated relatively to measure the total luminous flux of the light source.
Japanese Patent Laying-Open Nos. 62-250325, 07-294328, and 2003-247888 each disclose a configuration for measuring the luminous intensity distribution characteristic through a mirror provided at a position where the luminous intensity from a light source is to be measured, in contrast to the above-described configuration for measuring the total luminous flux.
The configurations and the methods disclosed in the above-referenced prior art documents have problems such as a problem of low versatility due to restriction of the type and/or size of the light source that can be measured and/or restriction of the photometric distance, and a problem of complication and increased size of the apparatus.